Electronic control device for a multi-fuel internal combustion engine

Abstract

With an electronic control device for an internal combustion engine using an oxygenated compound mixed fuel, operating conditions of the engine are detected, and are utilized to determine fundamental control data for the engine, while the dielectric constant and the refractive index of an oxygenated compound mixed fuel supplied to the engine are detected, and the oxygenated compound content of the mixed fuel is calculated according to the dielectric constant thus detected. The refractive index, and the oxygenated compound content are utilized to estimate the distillation characteristic of the petroleum refined fuel in the mixed fuel. The fundamental control data are corrected by using first correction data determined from the oxygenated compound content and second correction data determined from the distillation characteristic. Thus, with the device, the engine operates stably and correctly at low and middle temperatures irrespective of the oxygenated compound content of the mixed fuel or the nature of gasoline thereof.

What is claimed is: 
     
       1. An electronic control device for an internal combustion engine which can use a mixed fuel prepared by mixing oxygenated compound with a petroleum refined fuel, said electronic device comprising: operating condition detecting means for detecting operating conditions of said internal combustion engine;   dielectric constant detecting means for detecting a dielectric constant of said mixed fuel;   refractive index detecting means for detecting a refractive index of said mixed fuel;   oxygenated compound content calculating means for calculating an oxygenated compound content of said mixed fuel from a detection value provided by said dielectric constant detecting means;   distillation characteristic estimating means for estimating a representative quantity of a distillation characteristic of said petroleum refined fuel in said mixed fuel from a detection value provided by said refractive index detecting means and a calculation value provided by said oxygenated compound content calculating means;   fundamental control data determining means for determining fundamental control data of said internal combustion engine from a detection value provided by said operating condition detecting means;   means for determining first correction data from said calculation value provided by said oxygenated compound content calculating means;   means for determining second correction data from an estimation value provided by said distillation characteristic estimating means; and   means for correcting said fundamental control data with said first and second correction data.   
     
     
       2. The electronic control device according to claim 1, wherein said fundamental control data comprises data of a fuel injection quantity of said internal combustion engine and an ignition timing of an ignition plug of said internal combustion engine. 
     
     
       3. The electronic control device according to claim 2, wherein said operating condition detecting means detects whether said internal combustion engine is in one of a starting operation condition at low temperature, and an accelerating operation condition at low temperature. 
     
     
       4. The electronic control device according to claim 3, wherein said electronic control device correctively controls the fuel injection quantity and the ignition time of the ignition plug by using the oxygenated compound content of said mixed fuel and the distillation temperature of the petroleum refined fuel when said operating condition detecting means detects that said internal combustion engine is in one of said starting operation condition at low temperature and said accelerating operation condition at low temperature. 
     
     
       5. The electronic control device according to claim 3, wherein said electronic control device correctively controls the fuel injection quantity and the ignition time of the ignition plug by using the oxygenated compound content when said operating condition detecting means detects that said internal combustion engine is not in either of said operating conditions. 
     
     
       6. The electronic control device according to claim 1, wherein said operating condition detecting means comprises means for detecting a speed of rotation of said internal combustion engine, means for detecting a flow rate of air sucked into said internal combustion engine, means for detecting a throttle opening of said internal combustion engine, means for detecting an air-fuel ratio of said internal combustion engine and means for detecting a cooling water temperature of said internal combustion engine. 
     
     
       7. An electronic control device for an internal combustion engine which can use a mixed fuel prepared by mixing oxygenated compound with a petroleum refined fuel, said electronic control device comprising: operating condition detecting means for detecting operating conditions of said internal combustion engine;   fundamental control data determining means for determining fundamental control data of said internal combustion engine from said operating conditions thus detected;   refractive index detecting means for detecting a refractive index of said mixed fuel;   oxygenated compound content calculating means for calculating an oxygenated compound content of said mixed fuel from said refractive index;   means for determining first correction data from said oxygenated compound content thus calculated;   first correcting means for correcting said fundamental control data by using said first correction data;   air-fuel ratio detecting means for detecting an actual air-fuel ratio of said internal combustion engine;   comparing means for comparing said actual air-fuel ratio and a target air-fuel ratio to obtain a difference value;   second correcting means for correcting said calculated oxygenated compound content according to said difference value;   distillation characteristic estimating means for estimating a representative quantity of a distillation characteristic of said petroleum refined fuel of said mixed fuel from said oxygenated compound content thus corrected and said refractive index;   means for determining second correction data from said distillation characteristic thus estimated; and   means for utilizing said second correction data to correct said fundamental control data corrected with said first correction data.   
     
     
       8. The electronic control device according to claim 7, wherein said fundamental control data comprises data of a fuel injection quantity of said internal combustion engine and an ignition timing of an ignition plug of said internal combustion engine. 
     
     
       9. The electronic control device according to claim 8, wherein said operating condition detecting means detects whether said internal combustion engine is in one of a starting operation condition at low temperature and an accelerating operation condition at low temperature. 
     
     
       10. The electronic control device according to claim 9, wherein said electronic control device correctively controls the fuel injection quantity and the ignition time of the ignition plug by using the oxygenated compound content and the distillation temperature of the petroleum refined fuel when said operating condition detecting means detects that said internal combustion engine is in one of said starting operation condition at low temperature and said accelerating operation condition at low temperature. 
     
     
       11. The electronic control device according to claim 9, wherein said electronic control device correctively controls the fuel injection quantity and the ignition time of the ignition plug by using the oxygenated compound content when said operating condition detecting means detects that said internal combustion engine is in neither one of said operating conditions. 
     
     
       12. The electronic control device according to claim 7, wherein said operating condition detecting means comprises means for detecting a speed of rotation of said internal combustion engine, means for detecting a flow rate of air sucked into said internal combustion engine, means for a throttle opening of said internal combustion engine, and means for detecting a cooling water temperature of said internal combustion engine. 
     
     
       13. The device of claim 7 whereby said means for controlling said air-fuel ratio comprises a variable coefficient, whereby when said aimed air-fuel ratio is achieved, the value of said coefficient being correlated to the ratio of actual oxygenated compound content to said calculated oxygenated compound content and being communicated to said second correcting means so that a more accurate value of said calculated oxygenated compound can be obtained. 
     
     
       14. The device of claim 13 whereby said oxygenated compound content calculating means comprises predetermined data that correlate refractive indexes and compound contents, and said second correcting means uses said coefficient to update said predetermined data. 
     
     
       15. An electronic control device according to claim 7, further comprising means for controlling said air-fuel ratio of said internal combustion engine using the output of said first correcting means so that said air-fuel ratio reaches a target air-fuel ratio. 
     
     
       16. An electronic control device according to claim 13, wherein said difference value is the difference between said target air-fuel ratio and said air-fuel ratio thus detected.